Being a naturally suspicious person, Mr Law has no intention
of letting any Channel 5 retuners fiddle with his TV or video recorder. He has
a Sony VCR with a channel display and has checked to find which alternative
channels he can use for his VCR and satellite tuner. He thinks that only
channels 34 and 40 are free in his area but he fears channel 34 will become
unusable when C5 starts broadcasting. With only one spare channel available he
want to know what can be done, and what provision he can make for a laserdisc
player or DVD deck.

Expert reply:

No worries! Channel 5 interference wonít be a problem if you
connect your equipment together using SCART AV leads. You might need to re-tune
the VCR, to avoid a channel clash with C5 and your TV Ďvideoí channel but itís unlikely youíll only have
two free channels to play with. C5
tuning wonít be an issue if you get a laserdisc or DVD player as youíd be mad
to connect them to the TV using the aerial lead. The whole point about these
devices is the improved picture and sound quality, which would be barely
noticeable using an RF link (the audio will be mono too). If your VCR has 2
SCART sockets you can route the satellite tuner through it, otherwise the VCR
will have to go through the satellite tuner -- most current models have
three SCART sockets -- with the
connections clearly identified. If youíve got older or more basic equipment --
i.e. with just one SCART socket per box -- then either think about upgrading,
or get a SCART switch-box.

MORE DOSH, LESS TOSH

Name Henry Kavanagh,
Tenby

Kit Toshiba
2857DB DPL TV, Sony SLV-E710 VCR

Problem:

Henry is generally happy with his system but feels it lacks
impact in the surround-sound department. He wants to know if there any simple
add-ons -- hopefully costing less than £200 -- that can improve the sound.

Expert reply:

Henryís system is wholly dependent on the Tosh TV, for DPL
processing, amplification and the speakers. Thereís nothing wrong with the TVís
Pro Logic decoder, and the amps work well enough but theyíre not very powerful.
The supplied speakers -- built into the cabinet and stand, plus a pair of rear effects speakers -- are simply
incapable of creating the kind of wide, dynamic soundstage and surround-sound
effects home cinema cries out for. A pair of outboard speakers for the right
and left stereo channels, and possibly some more efficient effects speakers as
well, would definitely help. The TV has a set of speaker outputs, so theyíre
easy to fit and well within your budget. However, the TVís audio amplifier is the weak link, but unless youíre
willing to start again from scratch and spend quite a bit more, on a beefy AV
amp/DPL processor, speakers and probably a sub-woofer as well, Iím afraid
thereís not much you can do about it.

FLAT FOUR

Name: Paul Myhill

Kit: Sony KV-28W53V, Sony SLV-E80 VCR

Problem: Paul thinks he might have a problem with his Sony
widescreen TV. Channels 1, 2 and 3 are fine, however, the picture on Channel 4
is rather grainy, he compares it with looking through a dirty window, and he
says the sound only ever seems to be in mono, with the odd burst of NICAM. He
says he has tried re-tuning several times without success, and has also tried
an aerial booster, which made a small improvement to the picture, but not the
sound.

Expert reply

The very slight frequency difference between C4 and the
other channels is unlikely to be the cause, so itís almost certainly not the
TV. I checked with the ITC engineering department and they confirmed that the
Belmont transmitter, which serves your area, has not suffered any power
reductions recently, and that C4 operates at the same power levels and polarity
as the other three channels, so itís not their fault either. That leaves just
one or two other possibilities. The most likely one is a reduction in signal
strength brought about by standing waves. This is usually a very localised
phenomenon, often caused by a reflected signal path, reacting with the direct
signal from the transmitter. The two signals effectively cancel each other out.
The cure could be something as simple as moving the aerial a few feet. Check with
your neighbours, to see if theyíre suffering too. If not you might like to try
running a feed from their aerial -- you can get long extension cables from most
electrical retailers and woollies. If that does the trick then a call to your
local aerial installer is in order. If not your best bet is the local exorcist.

ANY BRIGHT IDEAS?

Name Steve Walker, Watford

Kit: JVC HR-D725

Problem:

Steveís old JVC HR-D725 VCR is doing some very strange
things. All of the segments in the front-panel display are brightly lit and the
machine only plays back for a few moments, at high speed, before shutting down.
He wants to know if itís a fault and if so, is there anything he can do as he
reckons heís quite handy with a soldering iron.

Expert reply:

Sorry Steve, bad news! Itís probably a goner by now. It
sounds as though a regulator transistor in the power supply has turned up its
toes, allowing the supply voltage to go sky high, probably taking with it a lot
of expensive semiconductors and chips in the process. Itís almost certainly
beyond economical repair by now. Get a quote by all means, but I reckon itís
going to cost a lot more than the machine is worth, to put it right.

PANEL GAME

Name Lennie Keene,
London SE

Kit Grundig
GRD200 satellite receiver, Amstrad dish

Problem:

Just over a year ago Lennie replaced his Amstrad satellite
receiver with a Grundig GRD 200. It worked perfectly until a couple of weeks
ago when the picture started breaking up. Now thereís just a pair of blank
white panels, superimposed over the top of an unscrambled picture. He wantís to
know if thereís a fault with the dish, or the receiver.

Expert reply:

Probably neither, itís most likely Lennieís Viewing Card is
faulty. The way to find out is to check Sky News, TNT/Cartoon Network and QVC
which are Ďsoftí scrambled, or unencrypted. If theyíre okay then it is almost
certainly the card. Try a full reset first. Remove the card, switch off and
unplug the decoder, then leaving it for a couple of minutes. Plug it back in
and wait for the Ďinsert cardí message and see what happens. If the fault
persists call BSKYB customer services on the number printed on the back of the
card. They will normally replace it within a couple of days. They will want
your old card though, so itís not a crafty way of getting a duplicate card. If
they donít get the original back in seven days theyíll switch the new one off.

WIDE BOYS

Name Greg Learman, Peckham

Kit: nothing yet, but in the market for a widescreen TV

Problem:

Greg is confused by widescreen TV. Heís been to see a
Grundig set, and was suitable impressed, but was troubled by the salespersonís
insistence that it would only work satisfactorily when used with a Grundig VCR,
which can record widescreen programmes. Can this be true?

Expert reply:

Theyíre pulling your pecker Greg, Grundig TVs might be a
bit, shall we say, idiosyncratic, but theyíre designed to work in the real
world, where they can end up being connected to just about any make of VCR.
Possibly the sales operative was keen to flog you a Grundig VCR as well, but
the only possible advantage would be a unified TV/VCR remote control. Donít be
fooled by talk of widescreen recording either; the only scheduled widescreen
transmissions in the UK right now are on Channel 4, which uses the PALplus
system.

The Only VCR with a built-in PALplus decoder is a three
grand digital jobbie from Sony. Many VHS machines have whatís fancifully
described as a 16:9 or widescreen facility, but this is simply a little circuit
that senses when a movie has been recorded Ďanamorphicallyí, where the picture
looks as though it has been squashed sideways. When the recording is replayed
on a widescreen TV, with a zoom or cinema mode, the picture is electronically stretched so that it fills the
width of the screen, and everything resumes normal proportions. Widescreen
switching is automatic on TVs and VCRs with the Ď16:9í facility. Thatís all
well and good, but the fact is there arenít any 16:9 movies available in the
UK, so the feature is practically worthless.

Mick has been using a speaker from a long-retired hi-fi
system for a centre speaker in his home cinema system. The speaker is placed on
top of the TV, where it has worked well for at least the past six months. Now
however, heís noticed a green patch on the top of the screen close to where the
speaker sits. Mick suspects itís due to the non-magnetically shielded speaker,
but canít understand why it has taken so long to appear.

Expert reply:

Itís likely the magnet in the speaker has been causing the
colour staining effect all the time. However, every time you switch the TV on a
circuit inside the set, connected to a coil attached to back of the picture
tube, briefly generates a collapsing magnetic field, that de-magnetises the
perforated metal sheet behind the tubeís face-plate. The Ďdegaussí circuit can
eradicate small magnetic fields that build up naturally -- from the Earthís own
magnetic field -- and from your speaker, but the fact that itís now
showing up on the screen suggests that
either degauss circuit has failed, or the build-up is now too large for your
set to handle.

The first step must be to remove the offending speaker, and
replace it with one thatís magnetically shielded, and hope that the degauss
circuit can gradually clean up the screen. If it canít or itís stopped working
then you will need help. TV engineers have access to portable heavy-duty
degauss coils; if itís a fault it should be relatively easy to fix.

HIGH END, OR OLD FRIEND?

Name: Andrew Pane, Stirchley

Kit: in the market for a surround sound decoder

Problem:

Whatís the difference between THX and Dolby Pro Logic?
Thatís what Andrew wants to know, and if he holds off buying a home cinema
system, will it get any cheaper?

Expert reply:

If it helps, think of THX (the Lucasfilm Tomlinson Holman
eXperiment) as a kind of supercharged Dolby Pro Logic surround sound. Itís DPL
with knobs on, a set of rigid specifications and enhancements covering the design
and construction of surround-sound components, to ensure an even more authentic
replication of the cinema experience, in your living room.

Briefly, and somewhat simplistically, it starts with a
conventional DPL decoder or active matrix. This is an electronic circuit that
unravels surround-sound information contained within a movieís stereo
soundtrack and Ďsteersí it, to the appropriate right, left, centre or rear
effects channel. Thatís the point where THX circuitry takes over. The right and
left stereo channels of movie soundtracks are engineered for large auditoria,
THX carefully re-equalises and balances the sound to suit smaller spaces. The
rear channel output is treated to Ďtimbre-matchingí, which ensures that it
blends in more smoothly with the front channels, as sounds move from back to
front, or vice-versa. A process known as de-correlation fiddles around with
front and rear channel delays, which helps reduce the distracting effect of
centre channel leakage. The THX specification also covers speaker design, to
ensure they can handle the full range of frequencies -- especially the bass
notes -- that movie-makers use to add impact to their productions.

That kind of electronic trickery and high performance
speakers costs big bucks, and the price of THX equipment is unlikely fall as
far or as fast as simpler DPL systems. Buy the best system you can afford, but
if you go down the THX route be warned that itís going to be expensive...

Neil is in complete despair. He says every video he rents or
buys is a gamble. He has to switch off the stereo soundtrack because of the
continuous noise that occurs, a constant raspberry sound coming out of the
speakers. His only solution is switch to mono, but he doesnít want to watch the
film in mono to begin with. This problem occurs with 90 per cent of the videos
he rents or buys, all are genuine (not pirated) copies.

Expert reply:

VHS video recorders with DFM (depth frequency multiplex)
stereo hi-fi sound systems are very sensitive to mis-tracking, which produces
the characteristic Ďraspberryí sound Neil describes. It only takes a very
slight tracking error to make that noise, and you might not see any picture
disturbance. Virtually all VCRs nowadays have auto-tracking systems, but they
can only cope with minor errors, recorded on the tape. The fact that itís
happening with rented tapes, but not with tapes heís recorded (weíre assuming
thatís the case), implies thereís something wrong with the deck mechanism, and
in particular the adjustment of the tape guides. In severe cases you might spot
a tell-tale crease along the edge on the tape. In any event itís a job for an
engineer.

William has a biggish lounge measuring 30 x 13 feet, and is
thinking of trading in his Toshiba TV for a Philips 46P912 46-inch rear
projector. Alternatively he could keep the Tosh TV for normal viewing and get a
front projector. He has a budget of around £2500, he also want to know how much
screens cost, and what sort of size picture he can expect.

Expert reply:

Unfortunately William your budget doesnít give you much room
for manoeuvre and the Philips rear projection set is probably your best bet.
Youíre not going to get much change from £3000 for a half-decent front video
projector, though £4000 is a more realistic starting point. Cheaper models tend
to be single element LCD types, with lower wattage projection units. As far as
screen size is concerned, the skyís the limit. Most Ďdomesticí projectors will
throw up an image up to 100 inches across without any difficulty. A suitable
fold-away screen will add a further £150 to the bill; if youíre thinking about
motorised or sliding screens then reckon on another £500 or so.

Name: S. Law, Radlett

Kit: Sony TV

CENTRE CAUGHT?

Name: G Macdonald, Nottingham

Kit: Panasonic TX29AD1DP DPL TV, Yamaha YST SW60 active sub

Problem:

Adding the sub-woofer to Mr Macdonaldís Panasonic TV has
improved the bass output, but now he wants to do something about the dialogue.
This set generates a phantom centre channel from the right and left stereo
speakers; he would like to know if replacing the main speakers with a pair of
Canon S-25ís will help, and possibly Canon S-15ís for the rear effects
speakers.

Expert reply:

The S-25ís are good, but they canít perform miracles and in
any case they would be unsuitable for your set-up. Theyíre designed to create a
wide, well diffused stereo soundstage, that would tend to dilute the already
unfocused dialogue information even further. Using S-15s for the rear channel
might improve back/front balance slightly, and help reduce localisation on the
effects channel, but donít expect too much. Realistically changing the speakers
is not the answer, you really need to re-think the audio side, and consider a
separate AV amplifier.

Steven is suffering from distorted sound when he plays back
recordings through the VCR. He says it only happens at certain frequencies,
such as the opening sequence in the X-Files, or the piano music on Murder One.
The distortion is evident on the TV speakers, as well as the surround speakers
on all recordings (including rental movies) but not off-air broadcasts. Heís had the VCR checked by an authorised
service agent, but they found nothing wrong. Heís also tried changing SCART
leads, but to no avail, so now he want to know if we can help?

Expert reply

It has to be the VCR. Youíve proved thereís nothing wrong
with the TV or surround system. Itís
doubtful the service agent gave the hi-fi system more than a cursory once-over.
Take it back, and this time take a tape along with you, so they can hear the
distortion for themselves.